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Tool Hut
Tool Hut, ASE Certified Technician
Category: Chevy
Satisfied Customers: 515
Experience:  Owner of a mobile diagnostics company assisting auto technicians with difficult vehicles
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I have a 98 2.4 cavalier, throwing code 172. apart from

Customer Question

I have a 98 2.4 cavalier, throwing code 172.
apart from running rich , symptoms appear when engine is at operating temp.
Symptoms: stalling out at lights, rough idle, hesitation on acceleration from stop,
I have replaced the air temp sensor
a few misfires as of today on acceleration.
I have changed temperature sensor on the air duct before the throttle body - slight improvement for a day or 2 & back to issue.
Changed plugs next , again improvement but issue came back.
Changed upstream O2 sensor =no improvement
Submitted: 1 year ago.
Category: Chevy
Customer: replied 1 year ago.
i also removed the vaccum hose from the fuel pressure regulator, it was dry & no indication of gas
Expert:  Tool Hut replied 1 year ago.

Hi, My name is ***** ***** I have over 30 years experience repairing vehicles. ASE Certified Master Auto Technician I am confident we can fix this together. Can you tell me if this is a single OHC (overhead cam) 2.4 or a DOHC Dual Overhead Cam) or get me the 8th digit of your VIN. also when you removed the cover to replace your spark plugs what color was the plastic cover that has your spark plug wires hooked to it?

Customer: replied 1 year ago.
Customer: replied 1 year ago.
there is no plug wires on the 2.4
Customer: replied 1 year ago.
2.4 DOHC
Expert:  Tool Hut replied 1 year ago.

The short boots hook to a plastic cover that has the coils inside it. Those are considered plug wires. sorry for any confusion.

Expert:  Tool Hut replied 1 year ago.

When you removed the top to replace the spark plugs do you remember if the cover was white or black?

Customer: replied 1 year ago.
Customer: replied 1 year ago.
Booths are black , the plastic cover white
Customer: replied 1 year ago.
not 100% on the plastic cover
Expert:  Tool Hut replied 1 year ago.

I would take a spray bottle with water in it and spray a fine mist of water while the vehicle is running as good as you can under the cover without removing it. Not too much water just a mist. It would probably help to have someone inside car with vehicle in drive and brake depressed giving it just a little gas and see if you can make the miss get worse. I am suspecting one of your plug wire boots and/or your cover is cracked allowing spark to escape.

Customer: replied 1 year ago.
Is it possible to mist water under the cover, look terribly tight
Expert:  Tool Hut replied 1 year ago.

Yes its possible from the back side of engine. If you cannot get it in there you can remove the cover and look at the plastic part. If it is black it more than likely is bad. If it is white look for some apparent burn marks on it.